Cooled components for furnaces

ABSTRACT

To improve the resistance to abrasion during use of cooled components, such as tuyeres and stack and bosh coolers, in furnaces a refractory or a metal with greater abrasion resistance than the metal, which is normally copper or a copper alloy, used for the main body of the component is introduced during casting into the cast walls of the components. The added material may be in the form of one or more segments, a mesh, or in discrete particles and is located at or just below the surface at the nose (24) of the component. Examples of the materials which may be used are particles (44,48) of so-called &#34;hard metals&#34; which comprise hard sintered carbides, such as tungsten carbide; stainless steel meshes and expanded elements (10,40,42) of varying thickness; and various compressed refractories capable of withstanding the thermal shock in a matrix of copper.

TECHNICAL FIELD

This invention relates to cooled components used in furnaces,particularly blast furnaces.

BACKGROUND ART

Amongst the cooled components used in blast furnaces are the coolers,such as stack and bosh coolers, which are built into the refractorylining of the furnace, and tuyeres. These components are normallycastings of copper or copper alloy.

The noses of tuyeres and coolers inevitably become exposed to erosion bythe burden of ore, coke, limestone, etc., in the blast furnace, theexposure becoming progressively greater as the furnace lining wearsaway.

DISCLOSURE OF INVENTION

The object of the present invention is to improve the resistance toabrasion during use of cooled components for furnaces. For this purposeaccording to the present invention there is introduced into the castwalls of such components during casting a refractory or a metal withgreater abrasion resistance than the metal used for the main body of thecomponent. The added material may be a refractory or a metal in the formof one or more segments, a mesh or in discrete particles and is locatedat or just below the surface at the nose of the component.

The materials which may be used include

(a) so-called "hard metal" which comprises hard sintered carbides, suchas tungsten carbide,

(b) stainless steel meshes of varying thickness, and

(c) various compressed refractories capable of withstanding the thermalshock in a matrix of copper.

The materials concerned are introduced into the casting by locating themin position in the mould before casting is commenced.

A particularly suitable element is expanded metal from stainless steelor heat resistant steel. An expanded metal element has a certain amountof depth as well as length and breadth and the spaces between the steelstrips can be varied to give the desired gap, filled with the castcopper or other material, thus providing the desired good heatconduction from the exterior of the element to the cooling medium.

BRIEF DESCRIPTION OF THE DRAWINGS

Various forms of the invention will now be further described withreference to the accompanying drawings in which:

FIG. 1 is part of an expanded steel element which can be used for thepurposes of the invention;

FIG. 2 is a side view of a blast furnace cooler according to theinvention;

FIG. 3 is a section on a larger scale taken on the line III--III of FIG.2;

FIG. 4 is a similar part section showing a different type of abrasionresistant material; and

FIG. 5 is a section through a tuyere according to the invention.

BEST MODE OF CARRYING OUT THE INVENTION

FIG. 1 of the drawings shows part of an expanded stainless steelelement, generally designated by the reference numeral 10. This has beenmade in the usual way by cutting and expanding a sheet of stainlesssteel to give a lattice of strips 12 adjoined by flat nodes 14 which, asthey are twisted out of the plane of the paper as seen in FIG. 1, givesome depth to the structures as well as length and breadth. Spaces 16between the strips 12 and nodes 14 will be filled by the cast metal inthe finished article and will allow good conduction of heat to thesurface of the cast component.

The expanded sheet 10 can be cut to size and bent round very easily toform a curved or cylindrical shape.

Suitable gauge for the stainless steel sheet from which the element 10is made is 20 gauge (0.91 mm), and the stainless steel may be, forexample, according to BS1449 EN58B.

FIGS. 2 and 3 show, on a smaller scale than that used in FIG. 1, acooler, such as a bosh cooler, for a blast furnace. The cooler shown hasa main cooling compartment 18 with inlet and outlet apertures 20 and 22,the nose end 24 of the cooler being cooled by means of a cast-in waterpipe 26 having separate inlet and outlet 28 and 30.

The characterising feature of the cooler is the expanded stainless steelelement 10 which is included in the casting by locating it in positionin the casting mould and casting the copper of the cooler round it. Asshown in FIG. 2 it extends at length across the whole width of the noseof the cooler just underneath the surface and has been bent to go roundthe cast-in pipe 26 as shown in FIG. 3.

In FIG. 4 can be seen the nose of a cooler in which, instead of using anexpanded steel element 10, the abrasion resistant material consists ofparticles 48 of hard metal, i.e. mainly sintered tungsten carbide, suchas is used for carbide tips of cutting tools. No particular size orshape is needed for this particulate material and the particles may infact be waste hard metal from the manufacture of carbide tips or usedtips. The material 48 is embodied in the cooling element by placing itat the bottom of the mould or attached to the surface of the mould whenthe cooler is cast, so that the elements are embodied in the castcopper.

FIG. 5 shows a tuyere of the sort having a main cooling chamber 30surrounding an air-passage 32. The cooling chamber 30 has inlet andoutlet apertures 46. The nose 34 of the tuyere is cooled by a separatecooling pipe 36 having an inlet pipe 38 leading thereto and a similaroutlet pipe not seen in the section of FIG. 5.

The nose is reinforced with two rings of expanded metal, an inner ring40 which is inside the nose cooling pipe 36 and an outer ring 42 whichsurrounds the said pipe. Additionally hard metal particles 44 areembedded in the copper of the tuyere forwardly of the cooling pipe 36.

It will be understood that any constructional form of cooler or tuyerecan be used, the essential feature according to the invention being theprovision of the abrasion resistant material at the nose of the device.

Instead of using stainless steel, another form of heat-resistant steelcould also be used, for example, according to AISA 430/S15.

I claim:
 1. In a cast metallic component of high heat conductivity, andhaving cooling fluid passageways therein, for location in the lining ofa lined furnace, the component having a main body portion and a noseportion to be directed towards the interior of the furnace, theimprovement comprising an element chosen from the group consisting of amesh element and an expanded metal element embedded in said noseportion, said element having greater abrasion resistance than the metalof said cast component to reinforce said nose portion against abrasionby the charge in the furnace.
 2. The structure defined in claim 1wherein the component is a cooler for the wall of a blast furnace. 3.The structure defined in claim 1 wherein the component is a tuyere. 4.The structure defined in claim 1, 2 or 3 wherein the element is ofstainless steel.
 5. The structure defined in claim 1, 2 or 3 wherein theelement is of heat resistant steel.